In general, an air cleaner is an apparatus for discharging clean air after removing contaminants from indoor air containing fine dusts, various noxious gases, various germs, molds, viruses, etc., by using a purification medium. Such an air cleaner can be used through all seasons because it has various functions of removing unpleasant odors and small particles such as ticks, pollen and furs of pets, preventing an outbreak of disease due to an aerial infection, and so forth as well as its principal function of maintaining indoor air clean and pleasant.
Air cleaners can be largely classified into two types: dry type and wet type. Dry type air cleaners can be divided again into a filter type and an electric dust collection type.
As for the filter type air cleaner since various fine particles are captured while air passes through filters, the filter type air cleaner exhibits a high purifying efficiency, and thus is adequate for use in a season in which yellow dust comes. However, since the filters need to be replaced periodically, maintenance cost is high. The dust collection type air cleaner employs an electric dust collecting plate instead of a filter, so it has a merit in that there is no need to replace filters. However, if dusts are accumulated on the electric dust collecting plate, purifying efficiency of the air cleaner will be deteriorated, and dust removing capacity thereof will also be undermined.
Meanwhile, a wet type air cleaner employs a method for making floating particles in introduced air deposited in water by allowing the introduced air to contact water. The wet type air cleaner removes fine particles and microbe in the air with an adsorbing effect of mist particles by using air containing fine liquid particles generated by finely spraying water, fine liquid particles being smaller than or equal to about 0.5 μm.
One of such wet type air cleaners is disclosed in Japanese Patent Laid-open Publication No. 2000-334240, entitled “WET TYPE AIR CLEANER”.
The wet type air cleaner includes an air circulation passage through which air is introduced into the inside of the air cleaner and then is outputted to the outside after being purified and a reservoir containing liquid therein. The air cleaner further includes a blower unit for allowing the air to be circulated through the air circulation passage and a spray unit for spraying the liquid into a spray space in the air cleaner.
The blower unit includes a fan for drawing the air into the spray space and a motor for driving the fan. The spray unit includes a pump for pumping up the liquid from the reservoir and a nozzle for spraying the liquid into the spray space.
The air supplied into the air circulation passage typically flows downward after being introduced into the air cleaner from upside, whereas the liquid is sprayed upward from downside. Therefore, the air introduced into the air cleaner is brought into contact with fine liquid particles sprayed by the nozzle, thereby allowing noxious substances in the air to be adsorbed by the fine liquid particles.
In the conventional wet type air cleaners as described above, however, droplets adsorbing fine dust and dirt particles are discharged from the air cleaner together with purified air, thereby resulting in poor purification efficiency and an unexpected high humidity.
Further, the conventional wet type air cleaner has a drawback in that noise is increased by injecting water on an inner wall of the air cleaner to collect dusts or the like. Furthermore, in order to enhance the cleaning effect, a contact of the air containing dusts and the dispersed cleaning water needs to be increased. However, the contact between the cleaning water and the air is insufficient, so that the purification ability thereof is deteriorated.